1056 VARNISH 



with its bottom turned upwards for a minute, right over the boiling-pot. Observe, 

 that whenever the maker is beginning to pour, the assistant stands ready with a thick 

 piece of old carpet without holes, and sufficiently large to cover the mouth of the 

 boiling-pot should it catch fire during the pouring, which will sometimes happen if the 

 gum-pot is very hot ; should the gum-pot fire, it has only to be kept bottom upwards, 

 and it will go out of itself ; but if the boiling-pot should catch fire during the pouring, 

 let the assistant throw the piece of carpet quickly over the blazing pot, holding it 

 down all round the edges ; in a few minutes it will be smothered. The moment the 

 maker has emptied the gum-pot, he throws into it half-a-gallon of turpentine, and 

 with the swish immediately washes it from top to bottom, and instantly empties it into 

 the flat tin jack : he wipes the pot dry, and puts in 8 Ibs. more gum, and sets it upon 

 the furnace ; proceeding with this run exactly as with the last, and afterwards with 

 the third run. There will then be 8 gallons of oil, and 24 Ibs. of gum in the boiling- 

 pot, under which keep up a brisk strong fire until a scum or froth rises and tovei's 

 all the surface of the contents, when it will begin to rise rapidly. Observe, when it 

 rises near the rivets of the handles, carry it from the fire and set it on the ash-bed, 

 stir it down again, and scatter in the driers by a little at a time ; keep stirring, and if 

 the frothy head goes down put it upon the furnace, and introduce gradually the 

 remainder of the driers, always carrying out the pot when the froth rises near the 

 rivets. In general, if the fire be good, all the time a pot requires to boil from the 

 time of the last gum being poured in, is about three and a half or four hours : but 

 time is no criterion for a beginner to judge by, as it may vary according to the 

 weather, the quality of the oil, the quality of the gum, the driers, or the heat of the 

 fire, &c. ; therefore, about the third hour of boiling, try it on a bit of glass, and keep 

 it boiling, until it feels strong and stringy between the fingers ; it is then boiled 

 sufficiently to carry it on the ash-bed, and to be stirred down until it is cold enough 

 to mix, which will depend much on the weather, varying from half an hour in dry 

 frosty weather to one hour in warm summer weather. Previous to beginning to mix, 

 have a sufficient quantity of turpentine ready, fill the pot, and pour in, stirring 

 all the time at the top or surface, as before directed, until there are 15 gallons, or five 

 tins of oil of turpentine introduced, which will leave it quite thick enough if the gum 

 is good, and has been well run ; but if the gum was of a weak quality, and has not 

 been well fused, there ought to be no more than 12 gallons of turpentine mixed, and 

 even that may be too much. Therefore, when 12 gallons of turpentine have been 

 introduced, have a flat saucer at hand, and pour into it a portion of the varnish, and 

 in two or three minutes it will show whether it is too thick ; if not sufficiently thin, 

 add a little more turpentine, and strain it off quickly. As soon as the whole is stored 

 away, pour in the turpentine washings with which the gum-pots have been washed, 

 into the boiling- pot, and with the swish quickly wash down all the varnish from the pot 

 sides ; afterwards, with a large piece of woollen rag dipped in pumice-powder, wash 

 and polish every part of the inside of the boiling-pot, performing the same operation 

 on the ladle and stirrers ; rinse them with the turpentine washings, and at last rinse 

 them altogether in clean turpentine, which also put to the washings ; wipe dry with a 

 clean soft rag the pot, ladle, stirrer, and funnels, and lay the sieve so as to be com- 

 pletely covered with turpentine, which will always keep it from gumming up. The 

 foregoing directions concerning running the gum and pouring in the oil, and also 

 boiling off and mixing, are, with very little difference, to be observed in the making 

 of all sorts of copal varnishes, except the differences of the quantities of oil, gum, &c., 

 which will be found under the various descriptions by name, which will be hereafter 

 described. 



The choice of linseed oil is of peculiar consequence to the varnish-maker. Oil 

 from fine full-grown ripe seed, when viewed in a phial, will appear limpid, pale, and 

 brilliant ; it is mellow and sweet to the taste, has very little smell, is specifically 

 lighter than impure oil, and, when clarified, dries quickly and firmly, and does not 

 materially change the colour of the varnish when made, but appears limpid and 

 brilliant. 



Copal Varnishes for fine paintings, $c. Fuse 8 Ibs. of the very cleanest pale African 

 gum copal, and, when completely run fluid, pour in two gallons of hot oil, old measure ; 

 let it boil until it will string very strong ; and in about fifteen minutes, or while it is 

 yet very hot, pour in three gallons of turpentine, old measure, and got from the top of 

 a cistern. Perhaps during the mixing a considerable quantity of the turpentine will 

 escape ; but the varnish will be so much the brighter, transparent, and fluid ; and will 

 work freer, dry more quickly, and be very solid and durable when dry. After the 

 varnish has been strained, if it is found too thick, before it is quite cold, heat as much 

 turpentine, and mix with it, as will bring it to a proper consistency. 



Cabinet Varnish. Fuse 7 Ibs. of very fine African gum copal, and pour in half a 

 gallon of pale clarified oil ; in three or four mimrtes after, if it feel stringy, take it out 



